The Signature of All Things
by Jacob Boehme, translated by Anonymous [1912].A Christian mystic explains the hidden meanings implicit in everything.

The Secret Teachings of All Ages
by Manley Palmer Hall [1928]A comprehensive introduction to the Esoteric, including the Qaballa, Tarot, Ceremonial Magic, Neo-Platonic Philosophy, Mystery Religions, Rosicrucianism and Freemasonry.

The Gnostics and Their Remains
by Charles William King [1887]King's pioneering summary of what was known about the Gnostics prior to the Nag Hammadi discoveries.
Includes extensive discussion of Gnostic symbols and beliefs
among the Masons, Templars, Rosicrucians and Illuminati.

The Hieroglyphics of Horapollo
translated by Alexander Turner Cory [1840]An attempt in late antiquity to explain Egyptian Hieroglyphs as pure symbols (very unsuccessfully). Noted for its influence on later occultists.